Casting machine injector structure



Jan. 22, 1963 H. c. WERNECKE CASTING MACHINE INJECTOR STRUCTURE Filed March 26, 1958 3 Sheets-Sheet 1 -INVENTOR. HEINZ WERNECKE B Y M M M Jan. 22, 1963 H. c. WERNECKE 3,074,131

CASTING MACHINE INJECTOR STRUCTURE Filed March 26, 1958 3 Sheets-Sheet 2 F-IG- Z INVENTOR.

HEINZ WERNECKE ATTORNEX FIG- 3 Jan. 22, 1963 H. c. WERNECKE 3,074,131

CASTING MACHINE INJECTOR STRUCTURE Filed March 26, 1958 5 Sheets-Sheet 3 ////7////&

INVENTOR.

HEINZ WERNECKE V ATTORNEY United States Patent Ofifice 3,074,131 Patented Jan. 22, 1963 3,074,131 CASTING MACH-ENE KNJECTOR STRUQTURE Heinz C. Werneclre, 2703 Femclifi, Royal Oak, Mich. Filed Mar. 26, 1958, Ser. No. 724,208 1 Claim. c1. 22 ss This invention relates to die casting machines of the cold chamber type in which the casting material is melted externally of the machine and then is fed into the machine under pressure by an injector cylinder associated with the machine, and more particularly this invention relates to novel structure for such injector mechanism.

The cold chamber die casting machines known to the prior art include a shot sleeve which constitutes a high temperature resistant cylindrical passage feeding the die cavities and supported on the fixed platen of the machine. A pour hole allows molten casting material to be fed into the shot sleeve for injection into the die cavities. A hydraulically actuated injection cylinder is supported on the base of the machine removed from the fixed platen and has its cylinder rod drivingly connected with the shot piston, which is movable in the shot sleeve. Since each die has its injection point located at a point that is dependent upon the specific die shape it is necessary to vary the position of the shot sleeve and of the injection cylinder when the die is changed. As two separate adjustments must be made, each with respect to the die injection point with respect to each other, a difiicult alignment problem exists.

Other disadvantages of the present cold chamber injector mechanisms result from the fact that the rod connecting the shot piston and the injector piston must be exposed so as to allow cooling lines to be attached to the shot piston through the cylinder rod. The exposed rod must be at least twice the length of the piston stroke to allow the cooling lines to clear during movement of the rod. The result is an overly long casting machine structure.

The present invention contemplates an injector structure in which the injecting cylinder is integral with and supported on the shot sleeve. In the particular embodiment contemplated, the injection cylinder is supported directly on the stationary platen and acts as a spacer between the platen and the shot sleeve. A direct connection is made between the shot piston, which forces the molten casting material into the die cavity, and the injection piston, which is movable in the injector cylinder. Because of this unitary structure, when the die is changed, it is only necessary to vary the position of one unit. Changes in dies may therefore be made with increased rapidity and accuracy.

The present invention also contemplates a novel cooling system for the shot piston in which the cooling lines pass through the shot piston as well as the piston rod. This feature allows the rod length to be limited to the length of the piston stroke and the entire machine is thereby shortened by this length.

An additional advantage of the present structure results from the molten casting material being retained within the machine by both the shot piston and the cylinder piston as well as the protective housing surrounding the two. Since the cooling lines need not be connected to the piston rod this area may be totally enclosed by the injector cylinder thereby eliminating the possibility of any molten metal splattering out of the machine from behind the shot piston.

In the system of the present invention, since it is not necessary to adjust the injector cylinder independently on its own support, more freedom may be allowed in determining the injection point on the die and the position of the injection point with respect to the fixed platen. Since a single adjustment aligns both the injector cylinder and the shot cylinder with the injection point no difiiculty is encountered in making that alignment at any point on the fixed platen.

Other objects, advantages and applications of the present invention will be made apparent by the following detailed description of an embodiment of the invention. The description makes reference to the accompanying drawings in which:

FIGURE 1 is a perspective view of a die casting machine embodying the present invention;

FIGURE 2 is a cross sectional view of the injector structure including the shot cylinder of the preferred embodiment taken along lines 2-2 of FIGURE 1;

FIGURE 3 is a cross sectional view of the die actuating mechanism of the preferred embodiment taken along line 33 of FIGURE 1; and

FIGURE 4 is a broken away, partial, sectional view of an alternative embodiment of the shot piston cooling mechanism.

The machine is supported on a base 10 which is preferably formed of Welded plate steel. A fixed platen 12 is mounted on the base 10 and is adapted to retain the fixed die half 14. The movable die half 16 is supported on a platen 18 which has its lower edge resting on hardened and ground ways 20' that are fixedly attached to the upper surface of the base 10.

Four tie rods 22 which have one end fixed to the movable platen 18 and have their other end attached to the cylinder end 24 of a hydraulically actuated ram generally indicated at 26. Nuts 28 connect the threaded ends of the rods 22 to a head plate 30 on the ram 26. As is seen in FIGURE 3, the rods 22 pass through bushings 32 which are disposed in a cylinder support bracket 34. The bracket 34 is supported on its outer edges by brackets 36 which are adjustably attached to the base 10 by means of bolts 38.

The rod 40 of the ram 26 has its outer end fixedly attached to the support plate 34. Therefore, the piston end 42 of the rod 41) remains stationary with respect to the base of the machine while the cylinder end 24 moves as fluid is admitted to the various ram chambers.

Although fluid may be admitted to the ram chambers in the normal manner with lines directly connecting to either end of the cylinder 24, it is preferred that fluid connections be made internally through the plate 34 and the rod 40. For this purpose, the fluid conduits 44 are cut in the support plate 34 and attached to the outlet ports of the fluid valve (not shown) at one of their ends. At their other ends they connect the two fluid passages 46 and the rod 40. One of the passages 46 outlets on one side of the piston 42 while the other fluid passage outlets on the opposite side of the piston.

Cushioning devices which are not shown may be provided to slow down the piston action as it nears either of both ends of the stroke.

The injector structure is generally indicated at 48. As seen in FlGURE 2 it includes a shot sleeve 66 which directly attaches to the fixed die half 14 by means of a flanged end 70 which operates in a groove 64 in the fixed platen 12. The position of the injection cylinder may be adjusted with respect to the fixed die half by moving it to various positions along the groove 64. The shot sleeve 66 comprises a high temperature resistant liner which is internally coaxial to the injection cylinder 68 as its end nearest the platen. The shot sleeve extends beyond the fianged end 70 of the injection cylinder 68 and into the injection hole 60 of thefixed die half.

A pour hole 50 extends through both the injector cylinder 68 and the shot sleeve 66 so as to connect the internal Q hole in the shot sleeve 66 with the external side of the 3 injection cylinder. The molten casting material is introduced to the shot sleeve through the pour hole 50.

A shot piston 62 which also formed from a high temperature resistant alloy is positioned for movement within the shot sleeve 6 6. A connecting rod 72 has its extreme end connected to the shot piston 62 and has its other end connected to an injection piston 74 which is fitted for movement internally of the injection cylinder 68. A bulkhead 76 within the injection cylinder 68 separates the injector cylinder chamber from the shot sleeve chamber. Two fluid conduits 78 and 80 which are positioned at either end of the injection cylinder chamber and which connect. to the outer surface of the injection cylinder are utilized to admit and remove hydraulic fluid from the injection cylinder chamber and thereby actuate the injector piston 74 and its attached shot piston 62.

The connecting piston rod 72 extends beyond the rear end of the injection piston 74 as at 32, passing through the rear end 84 of the injection cylinder.

The rod 72 and its extension 82 each contain two concentric passages 86 and 88 which admit cooling fluid to the shot piston 62. The passages are interconnected within the piston 62 to allow a return flow. At their other extreme end they are connected to fluid lines 90 which admit and return cooling fluid from a pressurized piston (not shown). A sheet metal cover 92 protects the rear end of the rod 86 from exposure.

An alternative embodiment of the shot piston cooling system which may be employed when non-inflammable hydraulic fluid is used to drive the injection piston is illustrated in FIGURE 4. The injection cylinder 94 is equipped with a piston 96 and a connecting rod 98 which has two internal concentric fluid passages 13% and 1%. The central passage 102 connects through the piston 96 to its rear end through a check valve 1011 which allows fluid to pass in a rearward direction only. The outer fluid passage 160 connects to the internal end of the injection cylinder through means of the passage 1G6. As in the previous embodiment the fluid passages 162 connect with one another through a hollowed area in the shot piston 108.

To accomplish the injection stroke non-inflammable hydraulic fluid is admitted into the injection cylinder chamber rear of the injection piston through a passage 110. The check valve 191 prevents this fluid from entering the cooling system. On the return stroke fluid is admitted to the other side of the injection piston 96, This fluid enters the outer cooling passage 100 through the port 106, passes through the shot piston 108 into the internal cooling passage 102 and is vented out of the in jection cylinder 94 through the check valve 101 and the passage 110. In this manner the same hydraulic fluid which produces the motion of the shot piston is used to cool that piston.

The latching mechanism of the casting machine operates as follows. After the die halves have been cleared by the action of the ram 26 a plurality oflatches 52 which are arranged about the periphery of the dies close over a lip 53 on the edge of the movable die 16. The latches are pivotably supported on trunnions 54 and operate in notches 56 cut in the surface of the fixed platen 12. Latches are provided at regular intervals along the side of the platen so that as many latches as are required may be utilized. The latches are actuated by small cylinders 53 which are supported on the outer side of the fixed platen 12 Cylinders 58 also receive their hydraulic fluid through lines which are internal of the fixed platen 12.

'A cavity 61 is provided in the base directly below the die halves so that the operator has complete access to the dies from all sides.

It is thus seen that the present invention allows a die casting machine of simple and compact construction to be designed which may be adjusted to various dies much more simply than machines of therprior art, and which provides greater safety thanthose machines.

Having thus described my invention, I claim:

In a die casting machine having a base, a platen fixed with respect to said base, a first die half supported on said platen, and a second die half movable into and out of cooperating relationship with said first die half, means for injecting molten casting material under pressure into the cavity formed by said die halves, said means comprising a high temperature resistant casing passing through said platen and first die half; a first, high temperature resistant piston movable in said casing; means for admitting molten casting material into said casing in such a position that it may be injected into said die by the movement of said first piston; a hydraulic ram having a cylinder and a second piston, said second piston being drivingly connected to said first piston by a rod; means for admitting hydraulic fluid under pressure into said hydraulic cylinder on either side of said piston; two fluid passages passing through said rod and communicating with one another internally of said first piston, and means for passing cooling fluid through said two passages, said means comprising a uni-directional fluid connection between one of said passages and the volume of the ram cylinder on one side of said second piston and a bidirectional fiuid coupling between the other passage and the ram cylinder volume on the other side of said second piston.

References Cited in the file of this patent UNITED STATES PATENTS 1,957,453 Foster May 8, 1934 2,217,239 Smith Oct. 8, 1940 2,484,344 Hiller Oct. 11, 1949 2,581,550 Misfeldt Jan. 8, 1952 2,786,234 Beyer Mar. 26, 1957 

